Method and apparatus for making cushioning and insulating material



M. A. CHAVANNES Oct. 10, 1967 METHOD AND APPARATUS FOR MAKING CUSHIONINGAND INSULATING MATERIAL 2 Sheets-Sheet 1 Filed Sept. 10, 1963 II s d KIOct. 10, 1967 M. A. CHAVANNES METHOD AND APPARATUS FOR MAKING CUSHIONINGAND INSULATING MATERIAL 2 Sheets-Sheet 2 Filed Sept. 10, 1963 T12 E- I II/I/I 1/I/T INVENTOR. Alma ,4. 67/4 nq/v/vss United States Patent3,346,438 METHOD AND APPARATUS FOR MAKING CUSH- IONIN G AND INSULATINGMATERIAL Marc A. Chavannes, Fort Lee, N.J., assignor to Sealed AirCorporation, Hawthorne, N.J., a corporation of New Jersey Filed Sept.10, 1963, Ser. No. 307,966 7 Claims. (Cl. 156210) This invention relatesto composite cushioning and insulating materials and more specificallyconcerns a new and improved cushioning material and the method andapparatus for the manufacture thereof.

Insulating and cushioning materials made of a variety of plastics arenormally fabricated of two layers, at least one of which is providedwith a plurality of embossments forming sealed pockets within thematerial. These pockets are necessarily arranged in spaced relationshipone to the others with the result that any individual pocket may bestressed independently of the surrounding pockets. In instances whereinthe material is used as an insulating element, the areas between thepockets do not afford the insulating characteristics of the areascontaining pockets. This invention overcomes these difiiculties andprovides a material affording both improved cushioning as well asinsulating characteristics.

Another object of this invention resides in a new and improved methodand apparatus for manufacture of cushioning materials, having improvedcushioning and insulating characteristics.

Another object of this invention embraces the provision of a new andimproved method and apparatus for manufacture of cushioning materialswherein wall portions of individual cells are sealed one to another forgreater strength.

Still another object of this invention resides in the provision of a newand improved plastic cushioning material wherein a plurality ofhermetically sealed air pockets are joined one to the others to form ineflfect a sealed honeycomb structure.

Another object of the invention resides in the provision of a new andimproved method and apparatus for the manufacture of cushioningmaterials wherein the wall portions of the individual cells extendoutwardly to and in close proximity to the walls of the adjoining cells.

A further object of this invention resides in a new and improvedmaterial wherein the top surfaces of embossments provide a substantiallycontinuous surface in generally parallel relationship to the layersealing the embossments.

A still further object of this invention resides in the provision of anew and improved cushioning material wherein a plurality of embossmentsare joined one to the others to form a relatively homogenous cellularstructure.

The above and other objects and advantages of this invention will becomemore apparent from the following description and accompanying drawingsforming part of this application.

In the drawings:

FIGURE 1 is a diagrammatic illustration of one embodiment of apparatusin accordance with the invention.

FIGURE 2 is an enlarged fragmentary section of the embossing roller ofFIGURE 1 having a portion of embossed material thereon.

FIGURE 3 is an enlarged fragmentary section of the compression rollerand pressure belt of FIGURE 1.

FIGURE 4 is a plan view of the cushioning material with spacedembossments as it is fed onto the compression roller.

7 FIGURE 5 is a cross-sectional view of FIGURE 4 taken along the line 55thereof.

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FIGURE 6 is a plan view of the improved cushioning material inaccordance with the invention.

FIGURE 7 is a cross section of the material shown in FIGURE 6 takenalong the line 7--7 thereof.

FIGURES 8 and 9 are cross-sectional views along the lines of FIGURES 7and showing modified forms of the improved cushioning material inaccordance with the invention.

The improved material in accordance with the invention embodies at leasttwo layers of a plastic material fused one to the other with at leastone of the layers having discrete embossments extending from one sidethereof and in closely spaced relationship. The side Walls of eachembossment are fused to the side walls of adjoining embossments so thatthe completed material affords the effect of a pair of spaced layers ofplastic having a honeycomb of air cells incorporated therebetween. Withthis arrangement, each air cell or embossment is laterally supported bythe surrounding embossments and as a result a substantially stronger,more durable cushioning material is obtained. Furthermore, by theelimination of the spaces between the adjoining embossments, theinsulating qualities of the material are substantially improved, andthere are no cracks or crevasses for the accumulation or collection offoreign matter.

While the material as described above may be fabricated in a variety ofmodes, one method and apparatus is illustrated in FIGURES 1 to 3. Inthese figures, the two layers of plastic material, which may be sheetsof a homogenous material or may comprise previously laminated sheets ofplastic materials having different properties, are generally denoted bythe numerals 10 and 11. One procedure for preheating the layers 10 and11 prior to treatment in accordance with the invention is disclosed inUS. Patent No. 3,142,599, entitled Method and Apparatus for MakingLaminated Cushioning Material and the Resultant Products, granted July28, 1964. In the event the layers are extruded immediately prior toembossment and lamination in accordance with this invention, it may bedesirable to lower the temperature of the extruded layers so that theywill have the proper embossing and laminating temperatures to effect thedesired result.

The layer or lamina 10 is fed onto the embossing roller 12 by means ofthe roller 13, which if necessary can be heated to raise or at leastmaintain the temperature of the layer 10 at its embossing and laminatingtemperature. The lamina 10 is embossed by roller 12 which preferablyincludes vacuum means for creating a plurality of closely spaceddepressions. The second lamina or layer 11 is fed onto the surface ofthe embossing roller 12 and in overlying relationship to lamina 10 byroller 15, which, similar to roller 13, may be provided with heatingelements to raise or at least maintain the temperature of lamina 11 atits fusing temperature. Roller 15 may be arranged to exert a slightpressure against the two laminae 10 and 11 as they are brought intooverlying relationship at 16, though in most applications utilizing thinplastic layers, the roller 15 need not be in pressure contact with thelayers 10 and 11. The lamina 11 is hermetically fused to the unembossedportions of lamina 10, hermetically sealing the embossments 17 which areclearly visible in the laminate 18 as it is stripped from the embossingroller 12 by stripping roller 19.

A magnified partial cross section of the embossing roller is shown inFIGURE 2, having a portion of the laminated material 18 thereon.Although the embossing depressions 20 in the surface of the embossingroller 12 are shown to have cylindrical configurations, it isunderstood, of course, that these depressions could be of a 0 differentsize and shape, such as may be used, for example, in connection with theforming of hexagonal embossments. The embossing roller 12 is providedwith The surface area of theemboss'ing roller 12 surrounding thedepressions 20 may carry an adhesion-resisting layer 23 of silicone orother similar material. Thesecoated surfaces prevent the heated laminafrom adhering to the roller 12 as the lamina is molded and subsequentlyfused with lamina 11 at 16.

Stripping roller 19 removes the embossed cushioning 'material 18 fromthe roller 12 after the material has been cooled'to complete the sealingprocedure. The material 18 is then conveyed through an oven 24 having aradiant heater 25 for heating at least the surface of the embossments 17to a temperature in the vicinity of the melting point of the plasticmaterial. By the use of heat rays of selected wavelength, the majorportion of the heat will be absorbed by layer 10 and the fluid entrappedin the sealed embossments 17 will receive a 7 minimum quantity of heat,thereby minimizing the expension of the fluid.

The heated laminate 18, upon leaving the oven 24, is directed about aroller 28 and onto the drum 26. The roller 28 together with thecooperating rollers 28' and 28" carries a belt 27 which rides over thesurface of the drum 26 and constitutes a compression element forcompressing the laminated material 18 as it passes between the belt andthe drum 26. If desirable, radiant heaters 27' may be used to maintainthe temperature of the embossments and insure a positive seal. In thiscase it is preferable to utilize a perforated belt 27 of suitableinsulating material. One or more of the rollers 28, 28 and '28" may alsobe cooled to maintain the desired belt temperature whether it bemetallic or insulating in order to produce a uniform product. 7

- The rollers 28, 28 and 28" are driven at a speed so that the belt 27will have a velocity corresponding to the peripheral velocity of thedrum 26. Since the embossed side of the laminate 18 is heated by theoven 24, when the material is placed under compression, the embossmentsor cells are compressed and the side walls of each cell are urged intocontact with the side walls of.

adjoining cells and are held until the laminate is cooled and the sealis effected. For this purpose, it is desirable to cool the drum orcompression cylinder 26.

In some instances it maybe desirable to provide means i for holding thelaminated material 18 firmly on the compression roller 26, and for thispurpose, a vacuum system may be employedsSuch a vacuum system is shownin FIGURE 3 which constitutes a magnified fragmentary section of theroller, 26 and cooperating belt 27. The roller 26 may be provided withacentral vacuum manifold and a plurality of radially disposed tubes 30connected with the manifold and opening into the surface of the roller.An area of the surface 29 of rollers 26 surrounding each conduit 30 ispreferably recessed or serrated as denoted by the numeral 31, and anoverlying layer of fabric be terminated just prior to the point ofremoval of the finished product from the roller 26 by means of theroller 28".

, With further reference to FIGURE 3, it will be observed that theembossments in layer 10 are compressed to cause the sidewalls 10' ofadjoining embossments to of fabricating the material in accordance withthe invention somewhat more clearly. In FIGURE 4, which is a plan viewof the embossed material, it will be observed that the embossments 17are in closely spaced relationship throughout the surface of thelaminated structure 18, and while they are shown in circular orcylindrical configuration, it is evident that the embossments could berectangular, hexagonal or of any other suitable shape. A cross-sectionalview of the structure of FIGURE 4 is shown in FIGURE 5. This is anenlarged view which illustrates the general configuration of theembossments 17 and the fusing of the areas between the embossments 17With the backing layer 11. When the structure shown in FIGURES 4 and 5is subjected to compressive stress as previously described, aconfiguration such as that shown in FIGURES 6 and 7 is obtained. Theembossments 17 assume an essentially hexagonal configuration since theside walls of each embossment are joined to the adjoining side wallsof'the surrounding embossments. While all of the embossments are joinedfirmly with the surrounding embossments, slight depressions are formedat the corners 17 of each hexagon which gives the resultant product aslight ripple effect on the embossed surface. This ripple however isvery slight, and'for all practical purposes, the resultant structuregives the appearance of a pair of spaced layers of plastic materialhaving cellularlike formations therebetween.

An enlarged cross-sectional view of the structure of FIGURE 6,is shownin FIGURE 7, and it will be seen that the side walls 10 of adjoiningembossments 17 are firmly fused with only a slight depression at thepoint 17'.

The improved cushioning material as describedabove affords a strongerand more durableproduct since each of the aircells or embossments 17 isradially supported by the surrounding embossments, and there is no placefor the accumulation of dirt or other foreign material. Furthermore, byreason of the joinder of the side walls, improved insulatingcharacteristics are obtained. The cellular material in accordance withthe invention may also be subjected to further embossing processes whichsnakes it particularly adaptable for use in packaging and nate modes inwhich the side walls of the embossments 17 may be formed. It was pointedout in connection with FIGURE 7 that the sidewalls 10' of theembossments were sealed substantially throughouttheir extent as shown inthat figure. In some cases it may be desirable to seal only a portion ofthe side walls 10' and this partial sealing of the side walls is shownat 40 in FIGURE 8; To accomplish this mode of sealing, the pressureeffected by the belt 27 in FIGURE 1 is reduced so that the em-vbossments 17 are compressed just enoughto bring the upper edges of theadjoining embossments into contact one with the others. Under certainconditions, it may be desirable to provide a material configurationwherein the side walls of the embossments 17 are disposed in closeproximity one to'the others but are not in effect sealed.

A somewhat softer cushioning material is obtained.

throughout initial degrees of compression, though with substantialcompression, the walls do move in contact one with the others. This formof the invention is shown in FIGURE 9, and it will be observed that asmaller gap. exists between the side walls 10' of the embossments 17. Asin the case of theembodiment shown in FIGURE 8,

the structure in FIGURE 9 is obtained by further decreasing the pressureefi'ected by the belt 27.

The material in accordance with the invention may be made in continuoussheets of any desired width and is useful for a Wide variety ofapplications such as packaging, padding and insulating. In the lattercase, 48" material is particularly adaptable for use in the insulationof walls as the vertical studs are customarily placed on 12- inchcenters. In any event, the material need only be secured with enoughfasteners to prevent it from sagging or shifting in the course ofinstallation of the inner wall surface. In certain cases, it may bedesirable to puncture those cells overlying each stud to avoid possibledeformation of the wall surface when light wall board is used. Actualobservations have indicated that while insulation between the studs isimportant, a substantial amount of heat will be conducted by the studsso that the utilization of a plastic covering on the studs affords asubstantial improvement in reduction of heat conduction. This preventsloss of heat in the wintertime and also prevents the transfer of heatfrom the outer walls of the structure to the inner walls in thesummertime.

While only certain embodiments of the invention have been illustratedand described, it is apparent that modifications, alterations andchanges may be made without departing from the true scope and spiritthereof as defined by the appended claims.

What is claimed is:

1. The method of fabricating cushioning material comprising the steps ofheating a first plastic film, molding said heated film to provide aplurality of closely spaced embossments, heating a second plastic filmto a fusing temperature and feeding it into overlying relationship Withthe unembossed portions of said first film to fuse said films throughoutthe unembossed portions of said first film and form a unitary structurehaving a plurality of closely spaced, hermetically sealed air pockets,heating at least the embossed surface of said structure to the meltingpoint of said plastic films, compressing said heated structure to fuseside walls of adjoining embossments one to the others, and cooling theresultant cushioning material.

2. The method for fabricating cushioning material comprising the stepsof heating two plastic laminae individually and simultaneously at leastuntil one surface of each of said laminae is heated to the vicinity ofthe melting point, providing one of said laminae with a plurality ofclosely spaced and uniformly distributed embossments, sealing saidembossments by bringing the other of said plastic laminae into overlyingpressure relationship with the unembossed surface of said one laminawith the molten surfaces of said two laminae facing each other to form alaminate having closely spaced fluid containing pockets evenlydistributed throughout, reheating at least the embossed surface of saidlaminate to the vicinity of the melting point of said plastic laminae,compressing the heated laminate to uniformly fuse side wall portions ofadjacent embossrnents one to the other, and cooling the resultantcushioning material.

3. The method of processing an embossed plastic cushioning materialcomprising the steps of heating at least the embossed surface of saidcushioning material to the vicinity of the melting point of the plasticmaterial, subjecting said material to compressive stress to fuse theconfronting side walls of said embossments one to the other and thencooling said material.

4. Apparatus for manufacturing insulative cushioning material comprisingmeans for embossing a first film of plastic, means for bonding a secondfilm of plastic to the unembossed portions of said first film to form aunitary structure having hermetically sealed pockets therein, means forproviding at least the embossed film of said unitary structure with abondable surface, and means for uniformly expanding the embossments inthe plane of said material to permanently bond confronting side walls ofadjacent embossments one to the other.

5. Apparatus for manufacturing insulative cushioning material comprisingmeans for embossing a first heated layer of plastic, means for bringinga second heated layer of plastic into overlying relationship with theunembossed portions of said first layer, means for urging said layers onsaid embossing means into pressure contact to form a unitary structurecontaining a plurality of closely spaced hermetically sealed airpockets, means for stripping the composite material from said embossingmeans, means for heating at least the embossed surface of said comoositematerial to the vicinity of the melting point thereof, means forexerting controlled pressure on said material to fuse confronting sideWalls of adjacent embossments one to the other, and means for strippingsaid material from said compressing means.

6. Apparatus for manufacturing insulating and cushioning materialcomprising an embossing roller having a plurality of closely spaceddepressions in its surface, vacuum means associated with said roller andcommunicating with each of said depressions, means for feeding a firstplastic film at a fusing temperature onto said embossing roller, meansfor bringing a second plastic film at a fusing temperature intooverlying pressure relationship with the unembossed portions of saidfirst film on said embossing roller to fuse said films into a unitarystructure having a plurality of closely spaced and hermetically sealedpockets therein, a stripping roller in close proximity of said embossingroller for removal of said unitary structure from said embossing roller,means for heating at least the embossed surface of said structure to thevicinity of the melting point of said integral films, and means forexerting uniform pressure over a substantial area of said heatedstructure to fuse the side walls of adjacent embossments one to theother to form a resultant material having two substantially smooth outersurfaces, and evenly spaced, double strength Walls defining saidpockets.

7. Apparatus for manufacturing an insulating and cushioning materialcomprising means for embossing a first film of plastic, means forbringing a second film of plastic into overlying relationship with theunembossed portions of said first film, the last said means includingmeans for urging said films into contact to form a unitary structurehaving closely spaced and evenly distributed hermetically sealed pocketstherein, a heating chamber including elements for raising thetemperature of at least the embossed surface of said unitary structureto the vicinity of the melting point of said plastic films, a relativelylarge compression roller including a porous covering thereon, vacuumconduits in said compression roller and opening into the surfacethereof, a continuous adhesion-resisting belt including driving andtension rollers therefor overlying at least part of the periphery ofsaid compression roller, means for feeding said unitary structurebetween said belt and compression roller, said belt exerting substantialcompressive stress on said structure to expand said embossmentslaterally, and cooling means for lowering the temperature of theresultant insulative cushioning material.

References Cited UNITED STATES PATENTS 2,020,639 11/1935 Grayson et al.161-123 X 2,556,011 6/1951 Swayze et a1. 156-595X 2,776,452 1/ 1957Chavannes 264- X FOREIGN PATENTS 908,579 10/ 1962 Great Britain.

EARL M. BERGERT, Primary Exiaminer. H. F. EPSTEIN, Assistant Examiner.

1. THE METHOD OF FABRICATING CUSHIONING MATERIAL COMPRISING THE STEPS OFHEATING A FIRST PLASTIC FILM, MOLDING SAID HEATED FILM TO PROVIDE APLURALITY OF CLOSELY SPACED EMBOSSMENTS, HEATING A SECOND PLASTIC FILMTO A FUSING TEMPERATURE AND FEEDING IT INTO OVERLYING RELATIONSHIP WITHTHE UNEMBOSSED PORTIONS OF SAID FIRST FILM TO FUSE SAID FILMS THROUGHOUTTHE UNEMBOSSED PORTIONS OF SAID FIRST FILM AND FORM A UNITARY STRUCTUREHAVING A PLURALITY OF CLOSELY SPACED, HERMETICALLY SEALED AIR POCKETS,HEATING AT LEAST THE EMBOSSED SURFACE OF SAID STRUCTURE TO THE MELTINGPOINT OF SAID PLASTIC FILMS, COMPRESSING SAID HEATED STRUCTURE TO FUSESIDE WALLS OF ADJOINING EMBOSSMENTS ONE TO THE OTHERS, AND COOLING THERESULTANT CUSHIONING MATERIAL.